draft-ietf-teas-actn-framework-13.txt   draft-ietf-teas-actn-framework-14.txt 
TEAS Working Group Daniele Ceccarelli (Ed) TEAS Working Group Daniele Ceccarelli (Ed)
Internet Draft Ericsson Internet Draft Ericsson
Intended status: Informational Young Lee (Ed) Intended status: Informational Young Lee (Ed)
Expires: October 3, 2018 Huawei Expires: November 11, 2018 Huawei
April 3, 2018 May 11, 2018
Framework for Abstraction and Control of Traffic Engineered Networks Framework for Abstraction and Control of Traffic Engineered Networks
draft-ietf-teas-actn-framework-13 draft-ietf-teas-actn-framework-14
Abstract Abstract
Traffic Engineered networks have a variety of mechanisms to Traffic Engineered networks have a variety of mechanisms to
facilitate the separation of the data plane and control plane. They facilitate the separation of the data plane and control plane. They
also have a range of management and provisioning protocols to also have a range of management and provisioning protocols to
configure and activate network resources. These mechanisms represent configure and activate network resources. These mechanisms represent
key technologies for enabling flexible and dynamic networking. The key technologies for enabling flexible and dynamic networking. The
term "Traffic Engineered network" refers to a network that uses any term "Traffic Engineered network" refers to a network that uses any
connection-oriented technology under the control of a distributed or connection-oriented technology under the control of a distributed or
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This Internet-Draft will expire on October 3, 2018. This Internet-Draft will expire on November 11, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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warranty as described in the Simplified BSD License. warranty as described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction...................................................3 1. Introduction...................................................3
2. Overview.......................................................4 2. Overview.......................................................4
2.1. Terminology...............................................5 2.1. Terminology...............................................5
2.2. VNS Model of ACTN.........................................7 2.2. VNS Model of ACTN.........................................7
2.2.1. Customers............................................9 2.2.1. Customers............................................9
2.2.2. Service Providers...................................10 2.2.2. Service Providers...................................10
2.2.3. Network Providers...................................10 2.2.3. Network Operators...................................10
3. ACTN Base Architecture........................................10 3. ACTN Base Architecture........................................10
3.1. Customer Network Controller..............................12 3.1. Customer Network Controller..............................12
3.2. Multi-Domain Service Coordinator.........................13 3.2. Multi-Domain Service Coordinator.........................13
3.3. Provisioning Network Controller..........................13 3.3. Provisioning Network Controller..........................13
3.4. ACTN Interfaces..........................................14 3.4. ACTN Interfaces..........................................14
4. Advanced ACTN Architectures...................................15 4. Advanced ACTN Architectures...................................15
4.1. MDSC Hierarchy...........................................15 4.1. MDSC Hierarchy...........................................15
4.2. Functional Split of MDSC Functions in Orchestrators......16 4.2. Functional Split of MDSC Functions in Orchestrators......16
5. Topology Abstraction Methods..................................17 5. Topology Abstraction Methods..................................17
5.1. Abstraction Factors......................................17 5.1. Abstraction Factors......................................17
5.2. Abstraction Types........................................18 5.2. Abstraction Types........................................18
5.2.1. Native/White Topology...............................18 5.2.1. Native/White Topology...............................18
5.2.2. Black Topology......................................18 5.2.2. Black Topology......................................19
5.2.3. Grey Topology.......................................19 5.2.3. Grey Topology.......................................20
5.3. Methods of Building Grey Topologies......................20 5.3. Methods of Building Grey Topologies......................21
5.3.1. Automatic Generation of Abstract Topology by 5.3.1. Automatic Generation of Abstract Topology by
Configuration..............................................21 Configuration..............................................21
5.3.2. On-demand Generation of Supplementary Topology via Path 5.3.2. On-demand Generation of Supplementary Topology via Path
Compute Request/Reply......................................21 Compute Request/Reply......................................21
5.4. Hierarchical Topology Abstraction Example................22 5.4. Hierarchical Topology Abstraction Example................22
5.5. VN Recursion with Network Layers.........................24 5.5. VN Recursion with Network Layers.........................24
6. Access Points and Virtual Network Access Points...............25 6. Access Points and Virtual Network Access Points...............25
6.1. Dual-Homing Scenario.....................................27 6.1. Dual-Homing Scenario.....................................27
7. Advanced ACTN Application: Multi-Destination Service..........28 7. Advanced ACTN Application: Multi-Destination Service..........28
7.1. Pre-Planned End Point Migration..........................29 7.1. Pre-Planned End Point Migration..........................29
7.2. On the Fly End-Point Migration...........................30 7.2. On the Fly End-Point Migration...........................30
8. Manageability Considerations..................................30 8. Manageability Considerations..................................30
8.1. Policy...................................................31 8.1. Policy...................................................31
8.2. Policy Applied to the Customer Network Controller........31 8.2. Policy Applied to the Customer Network Controller........32
8.3. Policy Applied to the Multi Domain Service Coordinator...32 8.3. Policy Applied to the Multi-Domain Service Coordinator...32
8.4. Policy Applied to the Provisioning Network Controller....32 8.4. Policy Applied to the Provisioning Network Controller....32
9. Security Considerations.......................................33 9. Security Considerations.......................................33
9.1. CNC-MDSC Interface (CMI).................................33 9.1. CNC-MDSC Interface (CMI).................................34
9.2. MDSC-PNC Interface (MPI).................................34 9.2. MDSC-PNC Interface (MPI).................................34
10. IANA Considerations..........................................34 10. IANA Considerations..........................................34
11. References...................................................34 11. References...................................................35
11.1. Informative References..................................34 11.1. Informative References..................................35
12. Contributors.................................................35 12. Contributors.................................................36
Authors' Addresses...............................................37 Authors' Addresses...............................................37
APPENDIX A - Example of MDSC and PNC Functions Integrated in A APPENDIX A - Example of MDSC and PNC Functions Integrated in A
Service/Network Orchestrator.....................................37 Service/Network Orchestrator.....................................37
1. Introduction 1. Introduction
The term "Traffic Engineered network" refers to a network that uses The term "Traffic Engineered network" refers to a network that uses
any connection-oriented technology under the control of a any connection-oriented technology under the control of a
distributed or centralized control plane to support dynamic distributed or centralized control plane to support dynamic
provisioning of end-to-end connectivity. Traffic Engineered (TE) provisioning of end-to-end connectivity. Traffic Engineered (TE)
networks have a variety of mechanisms to facilitate separation of networks have a variety of mechanisms to facilitate separation of
data plane and control plane including distributed signaling for data plane and control plane including distributed signaling for
path setup and protection, centralized path computation for planning path setup and protection, centralized path computation for planning
and traffic engineering, and a range of management and provisioning and traffic engineering, and a range of management and provisioning
protocols to configure and activate network resources. These protocols to configure and activate network resources. These
mechanisms represent key technologies for enabling flexible and mechanisms represent key technologies for enabling flexible and
dynamic networking. Some examples of networks that are in scope of dynamic networking. Some examples of networks that are in scope of
this definition are optical networks, MPLS Transport Profile (MPLS- this definition are optical networks, Multiprotocol Label Switching
TP) networks [RFC5654], and MPLS-TE networks [RFC2702]. (MPLS) Transport Profile (MPLS-TP) networks [RFC5654], and MPLS-TE
networks [RFC2702].
One of the main drivers for Software Defined Networking (SDN) One of the main drivers for Software Defined Networking (SDN)
[RFC7149] is a decoupling of the network control plane from the data [RFC7149] is a decoupling of the network control plane from the data
plane. This separation has been achieved for TE networks with the plane. This separation has been achieved for TE networks with the
development of MPLS/GMPLS [RFC3945] and the Path Computation Element development of MPLS/GMPLS [RFC3945] and the Path Computation Element
(PCE) [RFC4655]. One of the advantages of SDN is its logically (PCE) [RFC4655]. One of the advantages of SDN is its logically
centralized control regime that allows a global view of the centralized control regime that allows a global view of the
underlying networks. Centralized control in SDN helps improve underlying networks. Centralized control in SDN helps improve
network resource utilization compared with distributed network network resource utilization compared with distributed network
control. For TE-based networks, a PCE may serve as a logically control. For TE-based networks, a PCE may serve as a logically
centralized path computation function. centralized path computation function.
This document describes a set of management and control functions This document describes a set of management and control functions
used to operate one or more TE networks to construct virtual used to operate one or more TE networks to construct virtual
networks that can be represented to customers and that are built networks that can be represented to customers and that are built
from abstractions of the underlying TE networks so that, for from abstractions of the underlying TE networks so that, for
example, a link in the customer's network is constructed from a path example, a link in the customer's network is constructed from a path
or collection of paths in the underlying networks. We call this set or collection of paths in the underlying networks. We call this set
of function "Abstraction and Control of Traffic Engineered Networks" of functions "Abstraction and Control of Traffic Engineered
(ACTN). Networks" (ACTN).
2. Overview 2. Overview
Three key aspects that need to be solved by SDN are: Three key aspects that need to be solved by SDN are:
. Separation of service requests from service delivery so that . Separation of service requests from service delivery so that
the configuration and operation of a network is transparent the configuration and operation of a network is transparent
from the point of view of the customer, but remains responsive from the point of view of the customer, but remains responsive
to the customer's services and business needs. to the customer's services and business needs.
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specific technology islands) and presenting virtualized networks to specific technology islands) and presenting virtualized networks to
their customers. their customers.
The ACTN framework described in this document facilitates: The ACTN framework described in this document facilitates:
. Abstraction of the underlying network resources to higher-layer . Abstraction of the underlying network resources to higher-layer
applications and customers [RFC7926]. applications and customers [RFC7926].
. Virtualization of particular underlying resources, whose . Virtualization of particular underlying resources, whose
selection criterion is the allocation of those resources to a selection criterion is the allocation of those resources to a
particular customer, application or service [ONF-ARCH]. particular customer, application, or service [ONF-ARCH].
. TE Network slicing of infrastructure to meet specific customers' . TE Network slicing of infrastructure to meet specific
service requirements. customers' service requirements.
. Creation of an abstract environment allowing operators to view . Creation of an abstract environment allowing operators to view
and control multi-domain networks as a single abstract network. and control multi-domain networks as a single abstract network.
. The presentation to customers of networks as a virtual network . The presentation to customers of networks as a virtual network
via open and programmable interfaces. via open and programmable interfaces.
2.1. Terminology 2.1. Terminology
The following terms are used in this document. Some of them are The following terms are used in this document. Some of them are
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we mean a part of an operator's network that is under common we mean a part of an operator's network that is under common
management. Network elements will often be grouped into management. Network elements will often be grouped into
domains based on technology types, vendor profiles, and domains based on technology types, vendor profiles, and
geographic proximity. geographic proximity.
. Abstraction: This process is defined in [RFC7926]. . Abstraction: This process is defined in [RFC7926].
. TE Network Slicing: In the context of ACTN, a TE network slice . TE Network Slicing: In the context of ACTN, a TE network slice
is a collection of resources that is used to establish a is a collection of resources that is used to establish a
logically dedicated virtual network over one or more TE logically dedicated virtual network over one or more TE
network. TE Network slicing allows a network provider to networks. TE network slicing allows a network operator to
provide dedicated virtual networks for applications/customers provide dedicated virtual networks for applications/customers
over a common network infrastructure. The logically dedicated over a common network infrastructure. The logically dedicated
resources are a part of the larger common network resources are a part of the larger common network
infrastructures that are shared among various TE network slice infrastructures that are shared among various TE network slice
instances which are the end-to-end realization of TE network instances which are the end-to-end realization of TE network
slicing, consisting of the combination of physically or slicing, consisting of the combination of physically or
logically dedicated resources. logically dedicated resources.
. Node: A node is a vertex on the graph representation of a TE . Node: A node is a vertex on the graph representation of a TE
topology. In a physical network topology, a node corresponds topology. In a physical network topology, a node corresponds
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topology. Two nodes connected by a link are said to be topology. Two nodes connected by a link are said to be
"adjacent" in the TE topology. In a physical network topology, "adjacent" in the TE topology. In a physical network topology,
a link corresponds to a physical connection. In an abstract a link corresponds to a physical connection. In an abstract
network topology, a link (sometimes called an abstract link) is network topology, a link (sometimes called an abstract link) is
a representation of the potential to connect a pair of points a representation of the potential to connect a pair of points
with certain TE parameters (see [RFC7926] for details). with certain TE parameters (see [RFC7926] for details).
Network abstraction may be applied recursively, so a link in Network abstraction may be applied recursively, so a link in
one topology may be created by applying abstraction to the one topology may be created by applying abstraction to the
links in the underlying topology. links in the underlying topology.
. Abstract Link: The term "abstract link" is defined in
[RFC7926].
. Abstract Topology: The topology of abstract nodes and abstract . Abstract Topology: The topology of abstract nodes and abstract
links presented through the process of abstraction by a lower links presented through the process of abstraction by a lower
layer network for use by a higher layer network. layer network for use by a higher layer network.
. A Virtual Network (VN) is a network provided by a service . A Virtual Network (VN) is a network provided by a service
provider to a customer for the customer to use in any way it provider to a customer for the customer to use in any way it
wants as though it was a physical network. There are two views wants as though it was a physical network. There are two views
of a VN as follows: of a VN as follows:
a) The VN can be abstracted as a set of edge-to-edge links (a a) The VN can be abstracted as a set of edge-to-edge links (a
Type 1 VN). Each link is referred as a VN member and is Type 1 VN). Each link is referred as a VN member and is
formed as an end-to-end tunnel across the underlying formed as an end-to-end tunnel across the underlying
networks. Such tunnels may be constructed by recursive networks. Such tunnels may be constructed by recursive
slicing or abstraction of paths in the underlying networks slicing or abstraction of paths in the underlying networks
and can encompass edge points of the customer's network, and can encompass edge points of the customer's network,
access links, intra-domain paths, and inter-domain links. access links, intra-domain paths, and inter-domain links.
b) The VN can also be abstracted as a topology of virtual nodes b) The VN can also be abstracted as a topology of virtual nodes
and virtual links (a Type 2 VN). The provider needs to map and virtual links (a Type 2 VN). The operator needs to map
the VN to actual resource assignment, which is known as the VN to actual resource assignment, which is known as
virtual network embedding. The nodes in this case include virtual network embedding. The nodes in this case include
physical end points, border nodes, and internal nodes as well physical end points, border nodes, and internal nodes as well
as abstracted nodes. Similarly the links include physical as abstracted nodes. Similarly the links include physical
access links, inter-domain links, and intra-domain links as access links, inter-domain links, and intra-domain links as
well as abstract links. well as abstract links.
Clearly a Type 1 VN is a special case of a Type 2 VN. Clearly a Type 1 VN is a special case of a Type 2 VN.
. Access link: A link between a customer node and a provider . Access link: A link between a customer node and a operator
node. node.
. Inter-domain link: A link between domains under distinct . Inter-domain link: A link between domains under distinct
management administration. management administration.
. Access Point (AP): An AP is a logical identifier shared between . Access Point (AP): An AP is a logical identifier shared between
the customer and the provider used to identify an access link. the customer and the operator used to identify an access link.
The AP is used by the customer when requesting a VNS. Note that The AP is used by the customer when requesting a VNS. Note that
the term "TE Link Termination Point" (LTP) defined in [TE-Topo] the term "TE Link Termination Point" (LTP) defined in [TE-Topo]
describes the end points of links, while an AP is a common describes the end points of links, while an AP is a common
identifier for the link itself. identifier for the link itself.
. VN Access Point (VNAP): A VNAP is the binding between an AP and . VN Access Point (VNAP): A VNAP is the binding between an AP and
a given VN. a given VN.
. Server Network: As defined in [RFC7926], a server network is a . Server Network: As defined in [RFC7926], a server network is a
network that provides connectivity for another network (the network that provides connectivity for another network (the
Client Network) in a client-server relationship. Client Network) in a client-server relationship.
2.2. VNS Model of ACTN 2.2. VNS Model of ACTN
A Virtual Network Service (VNS) is the service agreement between a A Virtual Network Service (VNS) is the service agreement between a
customer and provider to provide a VN. When a VN is a simple customer and operator to provide a VN. When a VN is a simple
connectivity between two points, the difference between VNS and connectivity between two points, the difference between VNS and
connectivity service becomes blurred. connectivity service becomes blurred. There are three types of VNS
defined in this document.
There are three types of VNS defined in this document.
o Type 1 VNS refers to a VNS in which the customer is allowed o Type 1 VNS refers to a VNS in which the customer is allowed
to create and operate a Type 1 VN. to create and operate a Type 1 VN.
o Type 2a and 2b VNS refer to VNSs in which the customer is o Type 2a and 2b VNS refer to VNSs in which the customer is
allowed to create and operates a Type 2 VN. With a Type allowed to create and operates a Type 2 VN. With a Type
2a VNS, the VN is statically created at service 2a VNS, the VN is statically created at service
configuration time and the customer is not allowed to configuration time and the customer is not allowed to
change the topology (e.g., by adding or deleting abstract change the topology (e.g., by adding or deleting abstract
nodes and links). A Type 2b VNS is the same as a Type 2a nodes and links). A Type 2b VNS is the same as a Type 2a
VNS except that the customer is allowed to make dynamic VNS except that the customer is allowed to make dynamic
changes to the initial topology created at service changes to the initial topology created at service
configuration time. configuration time.
VN Operations are functions that a customer can exercise on a VN VN Operations are functions that a customer can exercise on a VN
depending on the agreement between the customer and the provider. depending on the agreement between the customer and the operator.
o VN Creation allows a customer to request the instantiation o VN Creation allows a customer to request the instantiation
of a VN. This could be through off-line pre-configuration of a VN. This could be through off-line pre-configuration
or through dynamic requests specifying attributes to a or through dynamic requests specifying attributes to a
Service Level Agreement (SLA) to satisfy the customer's Service Level Agreement (SLA) to satisfy the customer's
objectives. objectives.
o Dynamic Operations allow a customer to modify or delete the o Dynamic Operations allow a customer to modify or delete the
VN. The customer can further act upon the virtual network VN. The customer can further act upon the virtual network
to create/modify/delete virtual links and nodes. These to create/modify/delete virtual links and nodes. These
changes will result in subsequent tunnel management in the changes will result in subsequent tunnel management in the
operator's networks. operator's networks.
There are three key entities in the ACTN VNS model: There are three key entities in the ACTN VNS model:
- Customers - Customers
- Service Providers - Service Providers
- Network Providers - Network Operators
These entities are related in a three tier model as shown in Figure These entities are related in a three tier model as shown in Figure
1. 1.
+----------------------+ +----------------------+
| Customer | | Customer |
+----------------------+ +----------------------+
| |
VNS || | /\ VNS VNS || | /\ VNS
Request || | || Reply Request || | || Reply
\/ | || \/ | ||
+----------------------+ +----------------------+
| Service Provider | | Service Provider |
+----------------------+ +----------------------+
/ | \ / | \
/ | \ / | \
/ | \ / | \
/ | \ / | \
+------------------+ +------------------+ +------------------+ +------------------+ +------------------+ +------------------+
|Network Provider 1| |Network Provider 2| |Network Provider 3| |Network Operator 1| |Network Operator 2| |Network Operator 3|
+------------------+ +------------------+ +------------------+ +------------------+ +------------------+ +------------------+
Figure 1: The Three Tier Model. Figure 1: The Three Tier Model.
The commercial roles of these entities are described in the The commercial roles of these entities are described in the
following sections. following sections.
2.2.1. Customers 2.2.1. Customers
Basic customers include fixed residential users, mobile users, and Basic customers include fixed residential users, mobile users, and
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companies. Such customers ask for both point-to point and companies. Such customers ask for both point-to point and
multipoint connectivity with high resource demands varying multipoint connectivity with high resource demands varying
significantly in time. This is one of the reasons why a bundled significantly in time. This is one of the reasons why a bundled
service offering is not enough and it is desirable to provide each service offering is not enough and it is desirable to provide each
advanced customer with a customized virtual network service. advanced customer with a customized virtual network service.
Advanced customers may also have the ability to modify their service Advanced customers may also have the ability to modify their service
parameters within the scope of their virtualized environments. The parameters within the scope of their virtualized environments. The
primary focus of ACTN is Advanced Customers. primary focus of ACTN is Advanced Customers.
As customers are geographically spread over multiple network As customers are geographically spread over multiple network
provider domains, they have to interface to multiple providers and operator domains, they have to interface to multiple operators and
may have to support multiple virtual network services with different may have to support multiple virtual network services with different
underlying objectives set by the network providers. To enable these underlying objectives set by the network operators. To enable these
customers to support flexible and dynamic applications they need to customers to support flexible and dynamic applications they need to
control their allocated virtual network resources in a dynamic control their allocated virtual network resources in a dynamic
fashion, and that means that they need a view of the topology that fashion, and that means that they need a view of the topology that
spans all of the network providers. Customers of a given service spans all of the network operators. Customers of a given service
provider can in turn offer a service to other customers in a provider can in turn offer a service to other customers in a
recursive way. recursive way.
2.2.2. Service Providers 2.2.2. Service Providers
In the scope of ACTN, service providers deliver VNSs to their In the scope of ACTN, service providers deliver VNSs to their
customers. Service providers may or may not own physical network customers. Service providers may or may not own physical network
resources (i.e., may or may not be network providers as described in resources (i.e., may or may not be network operators as described in
Section 2.2.3). When a service provider is the same as the network Section 2.2.3). When a service provider is the same as the network
provider, this is similar to existing VPN models applied to a single operator, this is similar to existing VPN models applied to a single
provider although it may be hard to use this approach when the operator although it may be hard to use this approach when the
customer spans multiple independent network provider domains. customer spans multiple independent network operator domains.
When network providers supply only infrastructure, while distinct When network operators supply only infrastructure, while distinct
service providers interface to the customers, the service providers service providers interface to the customers, the service providers
are themselves customers of the network infrastructure providers. are themselves customers of the network infrastructure operators.
One service provider may need to keep multiple independent network One service provider may need to keep multiple independent network
providers because its end-users span geographically across multiple operators because its end-users span geographically across multiple
network provider domains. network operator domains. In some cases, service provider is also a
network operator when it owns network infrastructure on which
service is provided.
2.2.3. Network Providers 2.2.3. Network Operators
Network Providers are the infrastructure providers that provision Network operators are the infrastructure operators that provision
the network resources and provide network resources to their the network resources and provide network resources to their
customers. The layered model described in this architecture customers. The layered model described in this architecture
separates the concerns of network providers and customers, with separates the concerns of network operators and customers, with
service providers acting as aggregators of customer requests. service providers acting as aggregators of customer requests.
3. ACTN Base Architecture 3. ACTN Base Architecture
This section provides a high-level model of ACTN showing the This section provides a high-level model of ACTN showing the
interfaces and the flow of control between components. interfaces and the flow of control between components.
The ACTN architecture is based on a 3-tier reference model and The ACTN architecture is based on a 3-tier reference model and
allows for hierarchy and recursion. The main functionalities within allows for hierarchy and recursion. The main functionalities within
an ACTN system are: an ACTN system are:
skipping to change at page 11, line 11 skipping to change at page 11, line 13
This function includes network path computation based on This function includes network path computation based on
customer service connectivity request constraints, path customer service connectivity request constraints, path
computation based on the global network-wide abstracted computation based on the global network-wide abstracted
topology, and the creation of an abstracted view of network topology, and the creation of an abstracted view of network
resources allocated to each customer. These operations depend resources allocated to each customer. These operations depend
on customer-specific network objective functions and customer on customer-specific network objective functions and customer
traffic profiles. traffic profiles.
. Customer mapping/translation: This function is to map customer . Customer mapping/translation: This function is to map customer
requests/commands into network provisioning requests that can requests/commands into network provisioning requests that can
be sent to the Provisioning Network Controller (PNC) according be sent from the Multi-Domain Service Coordinator (MDSC) to the
to business policies provisioned statically or dynamically at Provisioning Network Controller (PNC) according to business
the OSS/NMS. Specifically, it provides mapping and translation policies provisioned statically or dynamically at the OSS/NMS.
of a customer's service request into a set of parameters that Specifically, it provides mapping and translation of a
are specific to a network type and technology such that network customer's service request into a set of parameters that are
specific to a network type and technology such that network
configuration process is made possible. configuration process is made possible.
. Virtual service coordination: This function translates customer . Virtual service coordination: This function translates customer
service-related information into virtual network service service-related information into virtual network service
operations in order to seamlessly operate virtual networks operations in order to seamlessly operate virtual networks
while meeting a customer's service requirements. In the while meeting a customer's service requirements. In the
context of ACTN, service/virtual service coordination includes context of ACTN, service/virtual service coordination includes
a number of service orchestration functions such as multi- a number of service orchestration functions such as multi-
destination load balancing, guarantees of service quality, destination load balancing, guarantees of service quality,
bandwidth and throughput. It also includes notifications for bandwidth and throughput. It also includes notifications for
service fault and performance degradation and so forth. service fault and performance degradation and so forth.
The base ACTN architecture defines three controller types and the The base ACTN architecture defines three controller types and the
corresponding interfaces between these controllers. The following corresponding interfaces between these controllers. The following
types of controller are shown in Figure 2: types of controller are shown in Figure 2:
. CNC - Customer Network Controller . CNC - Customer Network Controller
. MDSC - Multi Domain Service Coordinator . MDSC - Multi-Domain Service Coordinator
. PNC - Provisioning Network Controller . PNC - Provisioning Network Controller
Figure 2 also shows the following interfaces: Figure 2 also shows the following interfaces:
. CMI - CNC-MDSC Interface . CMI - CNC-MDSC Interface
. MPI - MDSC-PNC Interface . MPI - MDSC-PNC Interface
. SBI - South Bound Interface . SBI - Southbound Interface
+---------+ +---------+ +---------+ +---------+ +---------+ +---------+
| CNC | | CNC | | CNC | | CNC | | CNC | | CNC |
+---------+ +---------+ +---------+ +---------+ +---------+ +---------+
\ | / \ | /
Business \ | / \ | /
Boundary =============\==============|==============/============ Boundary =============\==================|=====================/=======
Between \ | / Between \ | /
Customer & ------- | CMI ------- Customer & ----------- | CMI --------------
Network Provider \ | / Network Operator \ | /
+---------------+ +---------------+
| MDSC | | MDSC |
+---------------+ +---------------+
/ | \ / | \
------------ | MPI ------------- ------------ | MPI ---------------
/ | \ / | \
+-------+ +-------+ +-------+ +-------+ +-------+ +-------+
| PNC | | PNC | | PNC | | PNC | | PNC | | PNC |
+-------+ +-------+ +-------+ +-------+ +-------+ +-------+
| SBI / | / \ | SBI / | / \
| / | SBI SBI / \ | / | SBI SBI / \
--------- ----- | / \ --------- ----- | / \
( ) ( ) | / \ ( ) ( ) | / \
- Control - ( Phys. ) | / ----- - Control - ( Phys. ) | / -----
( Plane ) ( Net ) | / ( ) ( Plane ) ( Net ) | / ( )
( Physical ) ----- | / ( Phys. ) ( Physical ) ----- | / ( Phys. )
( Network ) ----- ----- ( Net ) ( Network ) ----- ----- ( Net )
- - ( ) ( ) ----- - - ( ) ( ) -----
( ) ( Phys. ) ( Phys. ) ( ) ( Phys. ) ( Phys. )
--------- ( Net ) ( Net ) --------- ( Net ) ( Net )
----- ----- ----- -----
Figure 2: ACTN Base Architecture Figure 2: ACTN Base Architecture
Note that this is a functional architecture: an implementation and Note that this is a functional architecture: an implementation and
deployment might collocate one or more of the functional components. deployment might collocate one or more of the functional components.
3.1. Customer Network Controller 3.1. Customer Network Controller
A Customer Network Controller (CNC) is responsible for communicating A Customer Network Controller (CNC) is responsible for communicating
a customer's VNS requirements to the network provider over the CNC- a customer's VNS requirements to the network operator over the CNC-
MDSC Interface (CMI). It has knowledge of the end-points associated MDSC Interface (CMI). It has knowledge of the end-points associated
with the VNS (expressed as APs), the service policy, and other QoS with the VNS (expressed as APs), the service policy, and other QoS
information related to the service. information related to the service.
As the Customer Network Controller directly interfaces to the As the Customer Network Controller directly interfaces to the
applications, it understands multiple application requirements and applications, it understands multiple application requirements and
their service needs. The capability of a CNC beyond its CMI role is their service needs. The capability of a CNC beyond its CMI role is
outside the scope of ACTN and may be implemented in different ways. outside the scope of ACTN and may be implemented in different ways.
For example, the CNC may in fact be a controller or part of a For example, the CNC may in fact be a controller or part of a
controller in the customer's domain, or the CNC functionality could controller in the customer's domain, or the CNC functionality could
also be implemented as part of a provisioning portal. also be implemented as part of a service provider's portal.
3.2. Multi-Domain Service Coordinator 3.2. Multi-Domain Service Coordinator
A Multi-Domain Service Coordinator (MDSC) is a functional block that A Multi-Domain Service Coordinator (MDSC) is a functional block that
implements all of the ACTN functions listed in Section 3 and implements all of the ACTN functions listed in Section 3 and
described further in Section 4.2. The two functions of the MDSC, described further in Section 4.2. The two functions of the MDSC,
namely, multi domain coordination and virtualization/abstraction are namely, multi-domain coordination and virtualization/abstraction are
referred to as network-related functions while the other two referred to as network-related functions while the other two
functions, namely, customer mapping/translation and virtual service functions, namely, customer mapping/translation and virtual service
coordination are referred to as service-related functions. The MDSC coordination are referred to as service-related functions. The MDSC
sits at the center of the ACTN model between the CNC that issues sits at the center of the ACTN model between the CNC that issues
connectivity requests and the Provisioning Network Controllers connectivity requests and the Provisioning Network Controllers
(PNCs) that manage the network resources. (PNCs) that manage the network resources.
The key point of the MDSC (and of the whole ACTN framework) is The key point of the MDSC (and of the whole ACTN framework) is
detaching the network and service control from underlying technology detaching the network and service control from underlying technology
to help the customer express the network as desired by business to help the customer express the network as desired by business
needs. The MDSC envelopes the instantiation of the right technology needs. The MDSC envelopes the instantiation of the right technology
skipping to change at page 13, line 37 skipping to change at page 13, line 37
controls and manages the primitives to achieve functionalities as controls and manages the primitives to achieve functionalities as
desired by the CNC. desired by the CNC.
In order to allow for multi-domain coordination a 1:N relationship In order to allow for multi-domain coordination a 1:N relationship
must be allowed between MDSCs and PNCs. must be allowed between MDSCs and PNCs.
In addition to that, it could also be possible to have an M:1 In addition to that, it could also be possible to have an M:1
relationship between MDSCs and PNC to allow for network resource relationship between MDSCs and PNC to allow for network resource
partitioning/sharing among different customers not necessarily partitioning/sharing among different customers not necessarily
connected to the same MDSC (e.g., different service providers) but connected to the same MDSC (e.g., different service providers) but
all using the resources of a common network infrastructure provider. all using the resources of a common network infrastructure operator.
3.3. Provisioning Network Controller 3.3. Provisioning Network Controller
The Provisioning Network Controller (PNC) oversees configuring the The Provisioning Network Controller (PNC) oversees configuring the
network elements, monitoring the topology (physical or virtual) of network elements, monitoring the topology (physical or virtual) of
the network, and collecting information about the topology (either the network, and collecting information about the topology (either
raw or abstracted). raw or abstracted).
The PNC functions can be implemented as part of an SDN domain The PNC functions can be implemented as part of an SDN domain
controller, a Network Management System (NMS), an Element Management controller, a Network Management System (NMS), an Element Management
skipping to change at page 14, line 31 skipping to change at page 14, line 31
(_ _) (_ _) (_ _) (_ _)
(_ _) (_ _) (_ _) (_ _)
(_______) (_______) (_______) (_______)
Figure 3: PNC Domain Borders Figure 3: PNC Domain Borders
3.4. ACTN Interfaces 3.4. ACTN Interfaces
Direct customer control of transport network elements and Direct customer control of transport network elements and
virtualized services is not a viable proposition for network virtualized services is not a viable proposition for network
providers due to security and policy concerns. In addition, some operators due to security and policy concerns. In addition, some
networks may operate a control plane and as such it is not practical networks may operate a control plane and as such it is not practical
for the customer to directly interface with network elements. for the customer to directly interface with network elements.
Therefore, the network has to provide open, programmable interfaces, Therefore, the network has to provide open, programmable interfaces,
through which customer applications can create, replace and modify through which customer applications can create, replace and modify
virtual network resources and services in an interactive, flexible virtual network resources and services in an interactive, flexible
and dynamic fashion. and dynamic fashion.
Three interfaces exist in the ACTN architecture as shown in Figure Three interfaces exist in the ACTN architecture as shown in Figure
2. 2.
. CMI: The CNC-MDSC Interface (CMI) is an interface between a CNC . CMI: The CNC-MDSC Interface (CMI) is an interface between a CNC
and an MDSC. The CMI is a business boundary between customer and an MDSC. The CMI is a business boundary between customer
and network provider. It is used to request a VNS for an and network operator. It is used to request a VNS for an
application. All service-related information is conveyed over application. All service-related information is conveyed over
this interface (such as the VNS type, topology, bandwidth, and this interface (such as the VNS type, topology, bandwidth, and
service constraints). Most of the information over this service constraints). Most of the information over this
interface is agnostic of the technology used by Network interface is agnostic of the technology used by network
Providers, but there are some cases (e.g., access link operators, but there are some cases (e.g., access link
configuration) where it is necessary to specify technology- configuration) where it is necessary to specify technology-
specific details. specific details.
. MPI: The MDSC-PNC Interface (MPI) is an interface between an . MPI: The MDSC-PNC Interface (MPI) is an interface between an
MDSC and a PNC. It communicates requests for new connectivity MDSC and a PNC. It communicates requests for new connectivity
or for bandwidth changes in the physical network. In multi- or for bandwidth changes in the physical network. In multi-
domain environments, the MDSC needs to communicate with domain environments, the MDSC needs to communicate with
multiple PNCs each responsible for control of a domain. The multiple PNCs each responsible for control of a domain. The
MPI presents an abstracted topology to the MDSC hiding MPI presents an abstracted topology to the MDSC hiding
technology specific aspects of the network and hiding topology technology specific aspects of the network and hiding topology
skipping to change at page 15, line 39 skipping to change at page 15, line 39
are scalability, administrative choices, or putting together are scalability, administrative choices, or putting together
different layers and technologies in the network. In the case where different layers and technologies in the network. In the case where
there is a hierarchy of MDSCs, we introduce the terms higher-level there is a hierarchy of MDSCs, we introduce the terms higher-level
MDSC (MDSC-H) and lower-level MDSC (MDSC-L). The interface between MDSC (MDSC-H) and lower-level MDSC (MDSC-L). The interface between
them is a recursion of the MPI. An implementation of an MDSC-H them is a recursion of the MPI. An implementation of an MDSC-H
makes provisioning requests as normal using the MPI, but an MDSC-L makes provisioning requests as normal using the MPI, but an MDSC-L
must be able to receive requests as normal at the CMI and also at must be able to receive requests as normal at the CMI and also at
the MPI. The hierarchy of MDSCs can be seen in Figure 4. the MPI. The hierarchy of MDSCs can be seen in Figure 4.
Another implementation choice could foresee the usage of an MDSC-L Another implementation choice could foresee the usage of an MDSC-L
for all the PNCs related to a given technology (e.g. IP/MPLS) and a for all the PNCs related to a given technology (e.g., Internet
different MDSC-L for the PNCs related to another technology (e.g. Protocol (IP)/Multiprotocol Label Switching (MPLS)) and a different
OTN/WDM) and an MDSC-H to coordinate them. MDSC-L for the PNCs related to another technology (e.g., Optical
Transport Network (OTN)/Wavelength Division Multiplexing (WDM)) and
an MDSC-H to coordinate them.
+--------+ +--------+
| CNC | | CNC |
+--------+ +--------+
| +-----+ | +-----+
| CMI | CNC | | CMI | CNC |
+----------+ +-----+ +----------+ +-----+
-------| MDSC-H |---- | -------| MDSC-H |---- |
| +----------+ | | CMI | +----------+ | | CMI
MPI | MPI | | MPI | MPI | |
| | | | | |
+---------+ +---------+ +---------+ +---------+
| MDSC-L | | MDSC-L | | MDSC-L | | MDSC-L |
+---------+ +---------+ +---------+ +---------+
MPI | | | | MPI | | | |
| | | | | | | |
----- ----- ----- ----- ----- ----- ----- -----
| PNC | | PNC | | PNC | | PNC | | PNC | | PNC | | PNC | | PNC |
----- ----- ----- ----- ----- ----- ----- -----
skipping to change at page 16, line 26 skipping to change at page 16, line 28
Figure 4: MDSC Hierarchy Figure 4: MDSC Hierarchy
4.2. Functional Split of MDSC Functions in Orchestrators 4.2. Functional Split of MDSC Functions in Orchestrators
An implementation choice could separate the MDSC functions into two An implementation choice could separate the MDSC functions into two
groups, one group for service-related functions and the other for groups, one group for service-related functions and the other for
network-related functions. This enables the implementation of a network-related functions. This enables the implementation of a
service orchestrator that provides the service-related functions of service orchestrator that provides the service-related functions of
the MDSC and a network orchestrator that provides the network- the MDSC and a network orchestrator that provides the network-
related functions of the MDSC. This split is consistent with the related functions of the MDSC. This split is consistent with the
YANG service model architecture described in [Service-YANG]. Figure Yet Another Next Generation (YANG) service model architecture
5 depicts this and shows how the ACTN interfaces may map to YANG described in [Service-YANG]. Figure 5 depicts this and shows how
models. the ACTN interfaces may map to YANG models.
+--------------------+ +--------------------+
| Customer | | Customer |
| +-----+ | | +-----+ |
| | CNC | | | | CNC | |
| +-----+ | | +-----+ |
+--------------------+ +--------------------+
CMI | Customer Service Model CMI | Customer Service Model
| |
+---------------------------------------+ +---------------------------------------+
| Service | | Service |
********|*********************** Orchestrator | ********|*********************** Orchestrator |
* MDSC | +-----------------+ * | * MDSC | +-----------------+ * |
* | | Service-related | * | * | | Service-related | * |
* | | Functions | * | * | | Functions | * |
* | +-----------------+ * | * | +-----------------+ * |
* +----------------------*----------------+ * +----------------------*----------------+
* * | Service Delivery Model * * | Service Delivery Model
* * | * * |
* +----------------------*----------------+ * +----------------------*----------------+
* | * Network | * | * Network |
* | +-----------------+ * Orchestrator | * | +-----------------+ * Orchestrator |
* | | Network-related | * | * | | Network-related | * |
* | | Functions | * | * | | Functions | * |
* | +-----------------+ * | * | +-----------------+ * |
********|*********************** | ********|*********************** |
+---------------------------------------+ +---------------------------------------+
MPI | Network Configuration Model MPI | Network Configuration Model
| |
+------------------------+ +------------------------+
| Domain | | Domain |
| +------+ Controller | | +------+ Controller |
| | PNC | | | | PNC | |
| +------+ | | +------+ |
+------------------------+ +------------------------+
SBI | Device Configuration Model SBI | Device Configuration Model
| |
+--------+ +--------+
| Device | | Device |
+--------+ +--------+
Figure 5: ACTN Architecture in the Context of the YANG Service Figure 5: ACTN Architecture in the Context of the YANG Service
Models Models
5. Topology Abstraction Methods 5. Topology Abstraction Methods
Topology abstraction is described in [RFC7926]. This section Topology abstraction is described in [RFC7926]. This section
discusses topology abstraction factors, types, and their context in discusses topology abstraction factors, types, and their context in
the ACTN architecture. the ACTN architecture.
Abstraction in ACTN is performed by the PNC when presenting Abstraction in ACTN is performed by the PNC when presenting
available topology to the MDSC, or by an MDSC-L when presenting available topology to the MDSC, or by an MDSC-L when presenting
topology to an MDSC-H. This function is different to the creation topology to an MDSC-H. This function is different to the creation
of a VN (and particularly a Type 2 VN) which is not abstraction but of a VN (and particularly a Type 2 VN) which is not abstraction but
construction of virtual resources. construction of virtual resources.
5.1. Abstraction Factors 5.1. Abstraction Factors
As discussed in [RFC7926], abstraction is tied with policy of the As discussed in [RFC7926], abstraction is tied with policy of the
networks. For instance, per an operational policy, the PNC would networks. For instance, per an operational policy, the PNC would
not provide any technology specific details (e.g., optical not provide any technology specific details (e.g., optical
parameters for WSON) in the abstract topology it provides to the parameters for Wavelength Switched Optical Network (WSON) in the
MDSC. Similarly, policy of the networks may determine the abstract topology it provides to the MDSC. Similarly, policy of the
abstraction type as described in Section 5.2. networks may determine the abstraction type as described in Section
5.2.
There are many factors that may impact the choice of abstraction: There are many factors that may impact the choice of abstraction:
- Abstraction depends on the nature of the underlying domain - Abstraction depends on the nature of the underlying domain
networks. For instance, packet networks may be abstracted with networks. For instance, packet networks may be abstracted with
fine granularity while abstraction of optical networks depends on fine granularity while abstraction of optical networks depends on
the switching units (such as wavelengths) and the end-to-end the switching units (such as wavelengths) and the end-to-end
continuity and cross-connect limitations within the network. continuity and cross-connect limitations within the network.
- Abstraction also depends on the capability of the PNCs. As - Abstraction also depends on the capability of the PNCs. As
skipping to change at page 18, line 40 skipping to change at page 18, line 43
This section defines the following three types of topology This section defines the following three types of topology
abstraction: abstraction:
. Native/White Topology (Section 5.2.1) . Native/White Topology (Section 5.2.1)
. Black Topology (Section 5.2.2) . Black Topology (Section 5.2.2)
. Grey Topology (Section 5.2.3) . Grey Topology (Section 5.2.3)
5.2.1. Native/White Topology 5.2.1. Native/White Topology
This is a case where the PNC provides the actual network topology to This is a case where the PNC provides the actual network topology to
the MDSC without any hiding or filtering of information. I.e., no the MDSC without any hiding or filtering of information, i.e., no
abstraction is performed. In this case, the MDSC has the full abstraction is performed. In this case, the MDSC has the full
knowledge of the underlying network topology and can operate on it knowledge of the underlying network topology and can operate on it
directly. directly.
5.2.2. Black Topology 5.2.2. Black Topology
A black topology replaces a full network with a minimal A black topology replaces a full network with a minimal
representation of the edge-to-edge topology without disclosing any representation of the edge-to-edge topology without disclosing any
node internal connectivity information. The entire domain network node internal connectivity information. The entire domain network
may be abstracted as a single abstract node with the network's may be abstracted as a single abstract node with the network's
skipping to change at page 20, line 5 skipping to change at page 20, line 14
5.2.3. Grey Topology 5.2.3. Grey Topology
A grey topology represents a compromise between black and white A grey topology represents a compromise between black and white
topologies from a granularity point of view. In this case, the PNC topologies from a granularity point of view. In this case, the PNC
exposes an abstract topology containing all PNC domains border nodes exposes an abstract topology containing all PNC domains border nodes
and an abstraction of the connectivity between those border nodes. and an abstraction of the connectivity between those border nodes.
This abstraction may contain either physical or abstract This abstraction may contain either physical or abstract
nodes/links. nodes/links.
Two modes of grey topology are identified: Two types of grey topology are identified:
. In a type A grey topology type border nodes are connected by a . In a type A grey topology, border nodes are connected by a full
full mesh of TE links (see Figure 7). mesh of TE links (see Figure 7).
. In a type B grey topology border nodes are connected over a . In a type B grey topology, border nodes are connected over a
more detailed network comprising internal abstract nodes and more detailed network comprising internal abstract nodes and
abstracted links. This mode of abstraction supplies the MDSC abstracted links. This mode of abstraction supplies the MDSC
with more information about the internals of the PNC domain and with more information about the internals of the PNC domain and
allows it to make more informed choices about how to route allows it to make more informed choices about how to route
connectivity over the underlying network. connectivity over the underlying network.
..................................... .....................................
: PNC Domain : : PNC Domain :
: +--+ +--+ +--+ +--+ : : +--+ +--+ +--+ +--+ :
------+ +-----+ +-----+ +-----+ +------ ------+ +-----+ +-----+ +-----+ +------
skipping to change at page 21, line 48 skipping to change at page 22, line 11
when the MDSC needs to create a new VN, the MDSC can issue path when the MDSC needs to create a new VN, the MDSC can issue path
computation requests to PNCs with constraints matching the VN computation requests to PNCs with constraints matching the VN
request as described in [ACTN-YANG]. An example is provided in request as described in [ACTN-YANG]. An example is provided in
Figure 8, where the MDSC is creating a P2P VN between AP1 and AP2. Figure 8, where the MDSC is creating a P2P VN between AP1 and AP2.
The MDSC could use two different inter-domain links to get from The MDSC could use two different inter-domain links to get from
Domain X to Domain Y, but in order to choose the best end-to-end Domain X to Domain Y, but in order to choose the best end-to-end
path it needs to know what domain X and Y can offer in terms of path it needs to know what domain X and Y can offer in terms of
connectivity and constraints between the PE nodes and the border connectivity and constraints between the PE nodes and the border
nodes. nodes.
------- -------- ------- -------
( ) ( ) ( ) ( )
- BrdrX.1------- BrdrY.1 - - BrdrX.1------- BrdrY.1 -
(+---+ ) ( +---+) (+---+ ) ( +---+)
-+---( |PE1| Dom.X ) ( Dom.Y |PE2| )---+- -+---( |PE1| Dom.X ) ( Dom.Y |PE2| )---+-
| (+---+ ) ( +---+) | | (+---+ ) ( +---+) |
AP1 - BrdrX.2------- BrdrY.2 - AP2 AP1 - BrdrX.2------- BrdrY.2 - AP2
( ) ( ) ( ) ( )
------- -------- ------- --------
Figure 8: A Multi-Domain Example Figure 8: A Multi-Domain Example
The MDSC issues a path computation request to PNC.X asking for The MDSC issues a path computation request to PNC.X asking for
potential connectivity between PE1 and border node BrdrX.1 and potential connectivity between PE1 and border node BrdrX.1 and
between PE1 and BrdrX.2 with related objective functions and TE between PE1 and BrdrX.2 with related objective functions and TE
metric constraints. A similar request for connectivity from the metric constraints. A similar request for connectivity from the
border nodes in Domain Y to PE2 will be issued to PNC.Y. The MDSC border nodes in Domain Y to PE2 will be issued to PNC.Y. The MDSC
merges the results to compute the optimal end-to-end path including merges the results to compute the optimal end-to-end path including
the inter domain links. The MDSC can use the result of this the inter domain links. The MDSC can use the result of this
computation to request the PNCs to provision the underlying computation to request the PNCs to provision the underlying
networks, and the MDSC can then use the end-to-end path as a virtual networks, and the MDSC can then use the end-to-end path as a virtual
link in the VN it delivers to the customer. link in the VN it delivers to the customer.
skipping to change at page 24, line 9 skipping to change at page 24, line 17
black topology abstraction to MSDC-H in which each PNC domain is black topology abstraction to MSDC-H in which each PNC domain is
presented as a single virtual node. MDSC-H combines these two presented as a single virtual node. MDSC-H combines these two
topologies to create the abstraction topology on which it operates. topologies to create the abstraction topology on which it operates.
MDSC-H sees the whole four domain networks as four virtual nodes MDSC-H sees the whole four domain networks as four virtual nodes
connected via virtual links. connected via virtual links.
5.5. VN Recursion with Network Layers 5.5. VN Recursion with Network Layers
In some cases the VN supplied to a customer may be built using In some cases the VN supplied to a customer may be built using
resources from different technology layers operated by different resources from different technology layers operated by different
providers. For example, one provider may run a packet TE network operators. For example, one operator may run a packet TE network
and use optical connectivity provided by another provider. and use optical connectivity provided by another operator.
As shown in Figure 10, a customer asks for end-to-end connectivity As shown in Figure 10, a customer asks for end-to-end connectivity
between CE A and CE B, a virtual network. The customer's CNC makes a between CE A and CE B, a virtual network. The customer's CNC makes a
request to Provider 1's MDSC. The MDSC works out which network request to Operator 1's MDSC. The MDSC works out which network
resources need to be configured and sends instructions to the resources need to be configured and sends instructions to the
appropriate PNCs. However, the link between Q and R is a virtual appropriate PNCs. However, the link between Q and R is a virtual
link supplied by Provider 2: Provider 1 is a customer of Provider 2. link supplied by Operator 2: Operator 1 is a customer of Operator 2.
To support this, Provider 1 has a CNC that communicates to Provider To support this, Operator 1 has a CNC that communicates to Operator
2's MDSC. Note that Provider 1's CNC in Figure 10 is a functional 2's MDSC. Note that Operator 1's CNC in Figure 10 is a functional
component that does not dictate implementation: it may be embedded component that does not dictate implementation: it may be embedded
in a PNC. in a PNC.
Virtual CE A o===============================o CE B Virtual CE A o===============================o CE B
Network Network
----- CNC wants to create a VN ----- CNC wants to create a VN
Customer | CNC | between CE A and CE B Customer | CNC | between CE A and CE B
----- -----
: :
*********************************************** ***********************************************
: :
Provider 1 --------------------------- Operator 1 ---------------------------
| MDSC | | MDSC |
--------------------------- ---------------------------
: : : : : :
: : : : : :
----- ------------- ----- ----- ------------- -----
| PNC | | PNC | | PNC | | PNC | | PNC | | PNC |
----- ------------- ----- ----- ------------- -----
: : : : : : : : : :
Higher v v : v v Higher v v : v v
Layer CE A o---P-----Q===========R-----S---o CE B Layer CE A o---P-----Q===========R-----S---o CE B
Network | : | Network | : |
| : | | : |
| ----- | | ----- |
| | CNC | | | | CNC | |
| ----- | | ----- |
| : | | : |
*********************************************** ***********************************************
| : | | : |
skipping to change at page 25, line 4 skipping to change at page 25, line 15
Higher v v : v v Higher v v : v v
Layer CE A o---P-----Q===========R-----S---o CE B Layer CE A o---P-----Q===========R-----S---o CE B
Network | : | Network | : |
| : | | : |
| ----- | | ----- |
| | CNC | | | | CNC | |
| ----- | | ----- |
| : | | : |
*********************************************** ***********************************************
| : | | : |
Operator 2 | ------ |
Provider 2 | ------ |
| | MSDC | | | | MSDC | |
| ------ | | ------ |
| : | | : |
| ------- | | ------- |
| | PNC | | | | PNC | |
| ------- | | ------- |
\ : : : / \ : : : /
Lower \v v v/ Lower \v v v/
Layer X--Y--Z Layer X--Y--Z
Network Network
Where
--- is a link
=== is a virtual link
Figure 10: VN recursion with Network Layers Figure 10: VN recursion with Network Layers
6. Access Points and Virtual Network Access Points 6. Access Points and Virtual Network Access Points
In order to map identification of connections between the customer's In order to map identification of connections between the customer's
sites and the TE networks and to scope the connectivity requested in sites and the TE networks and to scope the connectivity requested in
the VNS, the CNC and the MDSC refer to the connections using the the VNS, the CNC and the MDSC refer to the connections using the
Access Point (AP) construct as shown in Figure 11. Access Point (AP) construct as shown in Figure 11.
------------- -------------
skipping to change at page 25, line 39 skipping to change at page 25, line 53
+---+ X ( ) Z +---+ +---+ X ( ) Z +---+
|CE1|---+----( )---+---|CE2| |CE1|---+----( )---+---|CE2|
+---+ | ( ) | +---+ +---+ | ( ) | +---+
AP1 - - AP2 AP1 - - AP2
( ) ( )
------------- -------------
Figure 11: Customer View of APs Figure 11: Customer View of APs
Let's take as an example a scenario shown in Figure 11. CE1 is Let's take as an example a scenario shown in Figure 11. CE1 is
connected to the network via a 10Gbps link and CE2 via a 40Gbps connected to the network via a 10 Gbps link and CE2 via a 40 Gbps
link. Before the creation of any VN between AP1 and AP2 the link. Before the creation of any VN between AP1 and AP2 the
customer view can be summarized as shown in Table 1. customer view can be summarized as shown in Table 1.
+----------+------------------------+ +----------+------------------------+
|End Point | Access Link Bandwidth | |End Point | Access Link Bandwidth |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
|AP id| CE,port | MaxResBw | AvailableBw | |AP id| CE,port | MaxResBw | AvailableBw |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
| AP1 |CE1,portX | 10Gbps | 10Gbps | | AP1 |CE1,portX | 10Gbps | 10Gbps |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
skipping to change at page 26, line 43 skipping to change at page 26, line 45
+----------+------------------------+ +----------+------------------------+
|End Point | Access Link Bandwidth | |End Point | Access Link Bandwidth |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
|AP id| PE,port | MaxResBw | AvailableBw | |AP id| PE,port | MaxResBw | AvailableBw |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
| AP1 |PE1,portW | 10Gbps | 10Gbps | | AP1 |PE1,portW | 10Gbps | 10Gbps |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
| AP2 |PE2,portY | 40Gbps | 40Gbps | | AP2 |PE2,portY | 40Gbps | 40Gbps |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
Table 2: AP - Provider View Table 2: AP - Operator View
A Virtual Network Access Point (VNAP) needs to be defined as binding A Virtual Network Access Point (VNAP) needs to be defined as binding
between an AP and a VN. It is used to allow for different VNs to between an AP and a VN. It is used to allow for different VNs to
start from the same AP. "It also allows for traffic engineering on start from the same AP. It also allows for traffic engineering on
the access and/or inter-domain links (e.g., keeping track of the access and/or inter-domain links (e.g., keeping track of
bandwidth allocation). A different VNAP is created on an AP for bandwidth allocation). A different VNAP is created on an AP for
each VN. each VN.
In this simple scenario we suppose we want to create two virtual In this simple scenario we suppose we want to create two virtual
networks. The first with VN identifier 9 between AP1 and AP2 with networks. The first with VN identifier 9 between AP1 and AP2 with
bandwidth of 1Gbps, while the second with VN identifier 5, again bandwidth of 1 Gbps, while the second with VN identifier 5, again
between AP1 and AP2 and with bandwidth 2Gbps. between AP1 and AP2 and with bandwidth 2 Gbps.
The provider view would evolve as shown in Table 3. The operator view would evolve as shown in Table 3.
+----------+------------------------+ +----------+------------------------+
|End Point | Access Link/VNAP Bw | |End Point | Access Link/VNAP Bw |
+---------+----------+----------+-------------+ +---------+----------+----------+-------------+
|AP/VNAPid| PE,port | MaxResBw | AvailableBw | |AP/VNAPid| PE,port | MaxResBw | AvailableBw |
+---------+----------+----------+-------------+ +---------+----------+----------+-------------+
|AP1 |PE1,portW | 10Gbps | 7Gbps | |AP1 |PE1,portW | 10 Gbps | 7 Gbps |
| -VNAP1.9| | 1Gbps | N.A. | | -VNAP1.9| | 1 Gbps | N.A. |
| -VNAP1.5| | 2Gbps | N.A | | -VNAP1.5| | 2 Gbps | N.A |
+---------+----------+----------+-------------+ +---------+----------+----------+-------------+
|AP2 |PE2,portY | 40Gbps | 37Gbps | |AP2 |PE2,portY | 4 0Gbps | 37 Gbps |
| -VNAP2.9| | 1Gbps | N.A. | | -VNAP2.9| | 1 Gbps | N.A. |
| -VNAP2.5| | 2Gbps | N.A | | -VNAP2.5| | 2 Gbps | N.A |
+---------+----------+----------+-------------+ +---------+----------+----------+-------------+
Table 3: AP and VNAP - Provider View after VNS Creation Table 3: AP and VNAP - Operator View after VNS Creation
6.1. Dual-Homing Scenario 6.1. Dual-Homing Scenario
Often there is a dual homing relationship between a CE and a pair of Often there is a dual homing relationship between a CE and a pair of
PEs. This case needs to be supported by the definition of VN, APs PEs. This case needs to be supported by the definition of VN, APs,
and VNAPs. Suppose CE1 connected to two different PEs in the and VNAPs. Suppose CE1 connected to two different PEs in the
operator domain via AP1 and AP2 and that the customer needs 5Gbps of operator domain via AP1 and AP2 and that the customer needs 5 Gbps
bandwidth between CE1 and CE2. This is shown in Figure 12. of bandwidth between CE1 and CE2. This is shown in Figure 12.
____________ ____________
AP1 ( ) AP3 AP1 ( ) AP3
-------(PE1) (PE3)------- -------(PE1) (PE3)-------
W / ( ) \ X W / ( ) \ X
+---+/ ( ) \+---+ +---+/ ( ) \+---+
|CE1| ( ) |CE2| |CE1| ( ) |CE2|
+---+\ ( ) /+---+ +---+\ ( ) /+---+
Y \ ( ) / Z Y \ ( ) / Z
-------(PE2) (PE4)------- -------(PE2) (PE4)-------
skipping to change at page 28, line 14 skipping to change at page 28, line 18
homing relationship would then be mapped against the VNAPs (since homing relationship would then be mapped against the VNAPs (since
other independent VNs might have AP1 and AP2 as end points). other independent VNs might have AP1 and AP2 as end points).
The customer view would be shown in Table 4. The customer view would be shown in Table 4.
+----------+------------------------+ +----------+------------------------+
|End Point | Access Link/VNAP Bw | |End Point | Access Link/VNAP Bw |
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
|AP/VNAPid| CE,port | MaxResBw | AvailableBw |Dual Homing| |AP/VNAPid| CE,port | MaxResBw | AvailableBw |Dual Homing|
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
|AP1 |CE1,portW | 10Gbps | 5Gbps | | |AP1 |CE1,portW | 10 Gbps | 5 Gbps | |
| -VNAP1.9| | 5Gbps | N.A. | VNAP2.9 | | -VNAP1.9| | 5 Gbps | N.A. | VNAP2.9 |
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
|AP2 |CE1,portY | 40Gbps | 35Gbps | | |AP2 |CE1,portY | 40 Gbps | 35 Gbps | |
| -VNAP2.9| | 5Gbps | N.A. | VNAP1.9 | | -VNAP2.9| | 5 Gbps | N.A. | VNAP1.9 |
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
|AP3 |CE2,portX | 40Gbps | 35Gbps | | |AP3 |CE2,portX | 50 Gbps | 45 Gbps | |
| -VNAP3.9| | 5Gbps | N.A. | NONE | | -VNAP3.9| | 5 Gbps | N.A. | NONE |
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
Table 4: Dual-Homing - Customer View after VN Creation Table 4: Dual-Homing - Customer View after VN Creation
7. Advanced ACTN Application: Multi-Destination Service 7. Advanced ACTN Application: Multi-Destination Service
A further advanced application of ACTN is in the case of Data Center A further advanced application of ACTN is in the case of Data Center
selection, where the customer requires the Data Center selection to selection, where the customer requires the Data Center selection to
be based on the network status; this is referred to as Multi- be based on the network status; this is referred to as Multi-
Destination in [ACTN-REQ]. In terms of ACTN, a CNC could request a Destination in [ACTN-REQ]. In terms of ACTN, a CNC could request a
VNS between a set of source APs and destination APs and leave it up VNS between a set of source APs and destination APs and leave it up
to the network (MDSC) to decide which source and destination access to the network (MDSC) to decide which source and destination access
points to be used to set up the VNS. The candidate list of points to be used to set up the VNS. The candidate list of source
source and destination APs is decided by a CNC (or an entity outside and destination APs is decided by a CNC (or an entity outside of
of ACTN) based on certain factors which are outside the scope of ACTN) based on certain factors which are outside the scope of ACTN.
ACTN.
Based on the AP selection as determined and returned by the network Based on the AP selection as determined and returned by the network
(MDSC), the CNC (or an entity outside of ACTN) should further take (MDSC), the CNC (or an entity outside of ACTN) should further take
care of any subsequent actions such as orchestration or service care of any subsequent actions such as orchestration or service
setup requirements. These further actions are outside the scope of setup requirements. These further actions are outside the scope of
ACTN. ACTN.
Consider a case as shown in Figure 14, where three data centers are Consider a case as shown in Figure 14, where three data centers are
available, but the customer requires the data center selection to be available, but the customer requires the data center selection to be
based on the network status and the connectivity service setup based on the network status and the connectivity service setup
skipping to change at page 30, line 12 skipping to change at page 30, line 28
|DC-D| |DC-C|<------------- |DC-D| |DC-C|<-------------
+----+ +----+ +----+ +----+
Figure 15: Pre-planned End-Point Migration Figure 15: Pre-planned End-Point Migration
7.2. On the Fly End-Point Migration 7.2. On the Fly End-Point Migration
Compared to pre-planned end point migration, on the fly end point Compared to pre-planned end point migration, on the fly end point
selection is dynamic in that the migration is not pre-planned but selection is dynamic in that the migration is not pre-planned but
decided based on network condition. Under this scenario, the MDSC decided based on network condition. Under this scenario, the MDSC
would monitor the network (based on the VN SLA) and notify the CNC would monitor the network (based on the VN Service-level Agreement
in case where some other destination AP would be a better choice (SLA) and notify the CNC in case where some other destination AP
based on the network parameters. The CNC should instruct the MDSC would be a better choice based on the network parameters. The CNC
when it is suitable to update the VN with the new AP if it is should instruct the MDSC when it is suitable to update the VN with
required. the new AP if it is required.
8. Manageability Considerations 8. Manageability Considerations
The objective of ACTN is to manage traffic engineered resources, and The objective of ACTN is to manage traffic engineered resources, and
provide a set of mechanisms to allow customers to request virtual provide a set of mechanisms to allow customers to request virtual
connectivity across server network resources. ACTN supports connectivity across server network resources. ACTN supports
multiple customers each with its own view of and control of a multiple customers each with its own view of and control of a
virtual network built on the server network, the network operator virtual network built on the server network, the network operator
will need to partition (or "slice") their network resources, and will need to partition (or "slice") their network resources, and
manage the resources accordingly. manage the resources accordingly.
skipping to change at page 32, line 5 skipping to change at page 32, line 16
8.2. Policy Applied to the Customer Network Controller 8.2. Policy Applied to the Customer Network Controller
A virtual network service for a customer application will be A virtual network service for a customer application will be
requested by the CNC. The request will reflect the application requested by the CNC. The request will reflect the application
requirements and specific service needs, including bandwidth, requirements and specific service needs, including bandwidth,
traffic type and survivability. Furthermore, application access and traffic type and survivability. Furthermore, application access and
type of virtual network service requested by the CNC, will be need type of virtual network service requested by the CNC, will be need
adhere to specific access control policies. adhere to specific access control policies.
8.3. Policy Applied to the Multi Domain Service Coordinator 8.3. Policy Applied to the Multi-Domain Service Coordinator
A key objective of the MDSC is to support the customer's expression A key objective of the MDSC is to support the customer's expression
of the application connectivity request via its CNC as set of of the application connectivity request via its CNC as set of
desired business needs, therefore policy will play an important desired business needs, therefore policy will play an important
role. role.
Once authorized, the virtual network service will be instantiated Once authorized, the virtual network service will be instantiated
via the CNC-MDSC Interface (CMI), it will reflect the customer via the CNC-MDSC Interface (CMI), it will reflect the customer
application and connectivity requirements, and specific service application and connectivity requirements, and specific service
transport needs. The CNC and the MDSC components will have agreed transport needs. The CNC and the MDSC components will have agreed
skipping to change at page 33, line 24 skipping to change at page 33, line 37
Several distributed ACTN functional components are required, and Several distributed ACTN functional components are required, and
implementations should consider encrypting data that flows between implementations should consider encrypting data that flows between
components, especially when they are implemented at remote nodes, components, especially when they are implemented at remote nodes,
regardless these data flows are on external or internal network regardless these data flows are on external or internal network
interfaces. interfaces.
The ACTN security discussion is further split into two specific The ACTN security discussion is further split into two specific
categories described in the following sub-sections: categories described in the following sub-sections:
. Interface between the Customer Network Controller and Multi . Interface between the Customer Network Controller and Multi-
Domain Service Coordinator (MDSC), CNC-MDSC Interface (CMI) Domain Service Coordinator (MDSC), CNC-MDSC Interface (CMI)
. Interface between the Multi Domain Service Coordinator and . Interface between the Multi-Domain Service Coordinator and
Provisioning Network Controller (PNC), MDSC-PNC Interface (MPI) Provisioning Network Controller (PNC), MDSC-PNC Interface (MPI)
From a security and reliability perspective, ACTN may encounter many From a security and reliability perspective, ACTN may encounter many
risks such as malicious attack and rogue elements attempting to risks such as malicious attack and rogue elements attempting to
connect to various ACTN components. Furthermore, some ACTN connect to various ACTN components. Furthermore, some ACTN
components represent a single point of failure and threat vector, components represent a single point of failure and threat vector,
and must also manage policy conflicts, and eavesdropping of and must also manage policy conflicts, and eavesdropping of
communication between different ACTN components. communication between different ACTN components.
The conclusion is that all protocols used to realize the ACTN The conclusion is that all protocols used to realize the ACTN
skipping to change at page 34, line 26 skipping to change at page 34, line 41
functions of the MDSC. functions of the MDSC.
9.2. MDSC-PNC Interface (MPI) 9.2. MDSC-PNC Interface (MPI)
Where the MDSC must interact with multiple (distributed) PNCs, a Where the MDSC must interact with multiple (distributed) PNCs, a
PKI-based mechanism is suggested, such as building a TLS or HTTPS PKI-based mechanism is suggested, such as building a TLS or HTTPS
connection between the MDSC and PNCs, to ensure trust between the connection between the MDSC and PNCs, to ensure trust between the
physical network layer control components and the MDSC. physical network layer control components and the MDSC.
Which MDSC the PNC exports topology information to, and the level of Which MDSC the PNC exports topology information to, and the level of
detail (full or abstracted) should also be authenticated and detail (full or abstracted), should also be authenticated, and
specific access restrictions and topology views, should be specific access restrictions and topology views should be
configurable and/or policy-based. configurable and/or policy-based.
10. IANA Considerations 10. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
11. References 11. References
11.1. Informative References 11.1. Informative References
[RFC2702] Awduche, D., et. al., "Requirements for Traffic [RFC2702] Awduche, D., et. al., "Requirements for Traffic
Engineering Over MPLS", RFC 2702, October 1999. Engineering Over MPLS", RFC 2702, September 1999.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path [RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture", IETF RFC Computation Element (PCE)-Based Architecture", IETF RFC
4655, August 2006. 4655, August 2006.
[RFC5654] Niven-Jenkins, B. (Ed.), D. Brungard (Ed.), and M. Betts [RFC5654] Niven-Jenkins, B. (Ed.), D. Brungard (Ed.), and M. Betts
(Ed.), "Requirements of an MPLS Transport Profile", RFC (Ed.), "Requirements of an MPLS Transport Profile", RFC
5654, October 2009. 5654, September 2009.
[RFC7149] Boucadair, M. and Jacquenet, C., "Software-Defined [RFC7149] Boucadair, M. and Jacquenet, C., "Software-Defined
Networking: A Perspective from within a Service Provider Networking: A Perspective from within a Service Provider
Environment", RFC 7149, April 2014. Environment", RFC 7149, March 2014.
[RFC7926] A. Farrel (Ed.), "Problem Statement and Architecture for [RFC7926] A. Farrel (Ed.), "Problem Statement and Architecture for
Information Exchange between Interconnected Traffic- Information Exchange between Interconnected Traffic-
Engineered Networks", RFC 7926, July 2016. Engineered Networks", RFC 7926, July 2016.
[RFC3945] Manning, E., et al., "Generalized Multi-Protocol Label [RFC3945] Manning, E., et al., "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture2, RFC 3945, October 2004. Switching (GMPLS) Architecture2, RFC 3945, October 2004.
[ONF-ARCH] Open Networking Foundation, "SDN architecture", Issue [ONF-ARCH] Open Networking Foundation, "SDN architecture", Issue
1.1, ONF TR-521, June 2016. 1.1, ONF TR-521, June 2016.
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